Home-Router: Access internal server using external ip [migrated]

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If I've got a typical home router -- say a Net Gear -- which has certain ports forwarded to a internal server, is there a way to tweak the router to let me access that internal server using the external IP address from within the same network? Is there a non-enterprise grade router that can handle this type of thing?
In case that was strangely worded, let me re-phrase with an example.
My external IP is 1.2.3.4.
My internal server is 10.4.3.100
Port 1178 is being forwarded from the router to 10.4.3.100.
I'd like to be able to be able to hit 10.4.3.100 from an internal ip of 10.4.3.10 by usi
(HowTos)

I'm setting up an Apache 2.2 Ubuntu web server for internal services that is also supposed to be accessed from outside our LAN. Our LAN has a single external IP that is the external IP of our RV042 Cisco router.

We have set up several A records on our external DNS server that point to this IP.